Thus far, Chelsea are finalising the most significant transfer deals of the mid-season market and, considering they are right in the thick of the Premier League title-race, the acquisitions they have acquired could prove influential in where this season's crown ends up.

The news that Juan Mata would transfer to Manchester United for £37m did not appear too plausible when it first broke earlier this week but it is all but secured, with a medical examination undergone today.

The timing of the deal has struck a nerve with Arsenal manager Arsene Wenger, as United and Chelsea do not play each other for the rest of the season, while Mata could be a difference-maker for David Moyes against Manchester City and the Gunners.

In this report, Wenger claims it could have been a clever tactical ploy by Jose Mourinho - but what can you do?

Having already completed the Nemanja Matic coup last week, who had been allegedly wanted by United also, Chelsea have beaten another Premier League club to the punch when it comes to the signature of in-demand Egyptian winger Mohamed Salah, wanted by Liverpool.

On the same day Mata appeared destined to be the latest addition at Old Trafford, Salah's name appeared under the radar in West London.

For a reported £11m, the only thing that could cancel the deal with FC Basel is if the player, who scored against Chelsea in the Champions League this season, fails a medical.

A statement on the club's official website said: 'Chelsea can confirm an agreement has been reached with FC Basel for the transfer of their 21-year-old attacking midfielder Mohamed Salah. The move is subject to the Egyptian international agreeing personal terms and completing a medical examination.'

Even with Matic and Salah coming in and Kevin de Bruyne and Juan Mata heading out, there may still be plenty transfer activity to come as The Telegraph believe Ross Barkley has been identified as a replacement for Mata while Foot Mercato claim that a difference in opinion over the valuation of centre back Kurt Zouma could see the Frenchman remain at Saint Etienne rather than join the Blues.

The Ligue 1 side want £20m, while Chelsea refuse to go higher than £15m, apparently.

Elsewhere, promising midfielder Josh McEachran has joined Wigan Athletic on a loan basis. He told the club's official website: 'Jose [Mourinho] told me at the start of the season that I needed game time this season to help my development. Wigan Athletic play football the right way, the manager has introduced a nice style of football so I think it’s going to be good to play under his system.'